Electromagnetic switch



I 1,646,943' Oct. 25,1927. H N WADE ELECTROMAGNETIG SWITCH Filed Aug,'7. 1919 A TTORNEY Patented CL 25, 1927.

. UNITED "STATES fPaieniorric.t

HENRY N. WADE, OF MILWAUKEE, WISCONSN, ASSIGNOR TO THECUTLER-HAIVI1\EERMFG. CO., OF MILWAUKEE, "VVISCONSIIFT,` A CORPORATION OF WISCONSIN.

ELECTROMAGNETIC swimcn.

Appiicauonzfned August 7, 1919. serial No. 315,803.

Another object is to provide a switch which may be readily designed andadjusted to respond at, a given frequency of the current suppliedthereto and to be unresponsive i at all higher frequencies.

Other objects and advantages of the invention will hereinafter appear.

The accompanying' drawing illustrates onev embodiment of the inventionwhich will now be described, it being understood that the embodimentillustrated is susceptible of various modifications without departingfrom the scope of the appended claims.

vIn the drawing,

Figure 1 is a side view of the switch, and

Fig'. 2 is a front view thereof.

The switch illustrated comprises a contact arm l of magnetic materialcoloperable with a stationary contact 2, said arm being 3 pivotallysupported on a magnet frame 3 which carries a winding 4 to effectattraction of said arm and a coil 5 to function as hereinafter setforth. The magnet frame `and stationary contact are fixed to aninsulating support 6 and a spring 7 is connected at one end to thecontact arm l and at its other end to a member 8 adjustably securedv tothe base to normally disengage said. arm from the stationary contact.

The magnet frame has parallel pole pieces 9, l() and 11 the pole pieces10 and 11 being formed integrally therewith. TheV 1ntermediate polepiece 10 which isrecta-ngular in cross section forms a supporting corefor the winding 4 and also servesl to pivotally support the contactarm,said pole piece having its end bifurcated to receive a block 12 fixed tosaid arm and carrying a -pm' 13 passing through .said block. The polepiece 5U 9 is cylindrical and forms a supporting core for coil 5, thelatter preferably compris ing a plurality of copper washers of varyingthickness. This pole piece is mounted on a threaded stud 14 projectingthrough the magnet frame and base and the washers 5 are detachably,secured thereonby screws 15 'threading into the magnet frame. The polepiece 11 which as best shown in F ig. 2 is V-shaped in cross section,serves as a stop for thelower end of the Contact arm l, said armcarrying an adjustable non-magnetic set screw 16 to engage said polepiece.

It will thus be observed that the magnetic fiuX of the winding 1 hasparallel paths through the pole pieces 9 and 11 respectively, whereby itproduces actuating and lockout pulls on the contact member, thearrangement being such that the actuating pull preponderates the lockoutpull eX- cept as hereinafter set forth. Further it will be observed thatif thewinding 4 is supplied with an alternating, pulsating or otherundulating current its magnetic flux which threads the coil 5 willinduce currents in the latter varying with the frequency of thecurrentsupplied to said winding 4, whereby coil 5 -will function as adamping coil to oppose the magnetic flux tending to attract the arm 1.Thus the coil 5 will cause a part Vof the flux to traverse the aforesaidparallel path through pole piece 11, the percentage of fluir traversingthis path varying with the damping currents induced in coil 5. The

' opposing effect of coil 5 as is well understood will increase with anincrease in frequency of the current supplied to winding -1 and willdecrease with a decrease in the frequency of such current whereby amaximum percentage of flux will be caused to traverse the pole piece 11at maximum frequency,V wliilea minimum j )eicent-age of flux will becaused to traverse saidpole piece at minimum frequency. Obviously,therefore, the switch willlte'nd to respond at a certain frequency andto lock out at all higher frequencies. Y j i The switch illustrated maybe adjusted in various ways for variationfof its sensitiveness throughwide range. For example, the sensitiveness of the switch may be variedby varying the size of coil.5 or by relative variation of the air gapsbetween the contact arm and the pole pieces 9 and 11 by adjustment ofthe set screw 16 or by varying the tension of the spring 7 to vary theforce opposing attraction of arm 1. With the coil 5 formed asillustrated the size thereof may be readily varied by removal of thedesired number of washers, the varying thickness of the washers enablinga number of variations exceeding the number of washers.

I/Vhile the switch illustrated is designed and adjusted to respond onlyat frequencies below a predetermined limit it is obvious that a switchembodying the same elements and principles might be made to respond onlywhen the frequency of the current supplied thereto exceeds a givenvlimit. Also various other modifications of the switch are possiblewithout departing from the scope ot' the appended claims.

What I claim as new and cure by Letters Patent is: y

l. In an electric switch, in combination a movable contact member,electromagnetic means to be supplied with anundulating current toproduce a magnetic flux for opdesire to seerating said member and a coilthreaded by such magnetic iluX to produce an opposingr magnetic fluxrendering said means inoperative tov actuate said member while thefrequency of the currentv supplied thereto `exceeds a given limit, saidcoil comprising a plurality washers of varying thickness.

2. In an electric switch in combination a movable contact vmember anelectromagnet having parallelmagnetic circuits whereby the magnetic liuxthereof producesiopposng 'pulls on said member and a damping coilscribed n'iy naine.

HENRY N. WADE.

